Double homozygous mice. The genetic background of these mice was a mixture of C57BL/6 (64%) and 129/Sv (36%). The "129/Sv" was a combination of at least 129S2/SvPas, 129S7/SvEvBrd-Hprt+, and 129X1/SvJ.

Homozygous mice. The genetic background was a mixture of C57BL/6 and 129X1/SvJ. (Note: This is a targeted mutation of exon 1beta of the Cdkn2a gene and therefore this mutation only affects p19ARF and not p16INK4a.)

Compound mutant mice. These mice were generated by crossing strains that had previously been fully backcrossed onto C57BL/6. The genetic background may also include some DBA/2J and/or some 129X1/SvJ and/or some 129S2/SvPas.

The genetic background was not specified but included at least some FVB/N and 129X1/SvJ. Mice were homozygous for Cdkn2atm1Cjs and also carried the Tg(CAG-sb10)1Dla and TgTn(sb-T2/Onc)68Dla transgenes.